This invention relates to an agglutination analyzing apparatus for analyzing agglutination patterns produced in response to an immunological agglutination reaction, and more particularly to an apparatus for identifying various kinds of blood types with the aid of agglutination patterns of blood corpuscles or for detecting various kinds of antibodies and various antigens in sample solutions (like viruses, proteins or the like) with the aid of agglutination patterns of not only blood corpuscles but also of particles of materials such as latex, carbon or the like.
In known analyzing apparatuses due to the agglutination reaction, reaction vessels and analyzing steps are different for respective components to be analyzed. For instance, in a known manual method for judging the blood type of ABO system, use was made of test tubes as the reaction vessels. In this method a sample blood is first contrifuged to separate red blood cells and serum from each other, and then a given amount of blood cells is mixed with a diluent to form a blood cell suspension of 2 to 5%. Then, a given amount of the blood cell suspension is delivered into a test tube into which anti-A-serum or anti-B-serum is also distributed. After the blood cells have been centrifuged, the test tube is shaken and it is confirmed with the naked eye whether or not agglutination is formed. In this case, the sample blood which produces agglutination together with A-type antibody, but does not produce agglutination together with B-type antibody is identified as A-type, the sample blood which produces agglutination exclusively with B-type antibody is judged to be B-type, the sample blood which forms agglutination with both A-type and B-type antibodies is determined to be AB-type, and sample blood which does not produce agglutination with either A-type and B-type antibodies is judged as O-type.
In order to detect and measure HBs antigen, a method has been proposed which makes use of a plastic plate, called a microplate, provided with a number of wells, i.e. reaction vessels each having a conical base surface. This conventional method makes use of a microplate having 10.times.12 wells, for example, and detects and prescribes the HBs antigen by the following procedure.
(1) Buffer solution specially prescribed for R-PHA method is introduced into each well of the microplate one drop (0.025 ml) at a time. PA0 (2) A test serum (0.025 ml) is added to the first well of a row. By using a diluter, the doubling dilution is performed along the row up to the last (tenth) well. PA0 (3) One drop of R-PHA buffer (0.025 ml) is added to a first row and one drop of R-PHA inhibition solution is added to a second row. PA0 (4) After the mixtures thus treated have been sufficiently agitated by a micromixer for 10 seconds, incurvation is effected for one hour at 37.degree. C. PA0 (5) A drop of R-PHA cells of 1% suspension (0.025 ml) is added to each well. PA0 (6) The mixtures are agitated by the micromixer for ten seconds to suspend the R-PHA cells uniformly. PA0 (7) After the mixtures thus treated have been made stationary at room temperature for one hour, agglutination patterns are detected.
In the T-PHA system for syphilis, different diluents of a sample serum are formed in the microplate and a reagent prepared by bonding syphilis viruses with red blood cells of sheep is added to the serum diluents. After natural segmentation, it is confirmed with the naked eye whether or not agglutination is formed.
As described above, in the analyzing methods due to immunological agglutination reaction different kinds of reaction vessels are used depending upon the test items and further successive steps are also different for respective items.
There has also been known a microtitor method in which use is made of the microplate as the reaction vessels and steps are partially automated. In this method, delivery of samples and reagents and detection of agglutination are carried out automatically, but other steps are effected manually. This is due to the fact that in the case of using the microplate, mechanism and operations are liable to be complicated and thus, it is extremely difficult to effect all the steps automatically. Further, the microtitor method has several disadvantages. Since the sample serum is delivered quantitatively with the aid of capillary phenomenon, it is necessary to first deliver diluent into each well in the microplate and then a tip of dilutor onto which a sample has been applied is immersed into the diluent to mix the serum and diluent. Such a step is very complicated as compared with normal delivery steps in the analyzing apparatuses and thus could be controlled only by means of complicated mechanisms. Further, the delivery amount is made always constant, because the capillary action is utilized and thus, the delivery amount could not be adjusted at will. Further, the mixed solution is applied to the dilutor and the sample is partially wasted. This becomes a serious drawback in a multi-item analyzer.
Moreover, if the delivery of the blood cell sample is effected before the serum sample delivery, an indefinite amount of the blood cell sample might be removed from the well. Therefore, in the microtitor system, the diluent delivery, serum delivery and blood cell delivery have to be performed in this order and thus, the mechanical arrangement or design might be restricted. Further, in the microtitor method, since use is made of the blood cell suspension of about 1%, the operation is liable to be very complicated as compared with the test tube method described above.
In a conventional method of identifying blood types, for example, which has heretofore been proposed, use was made of a winecup-shaped reaction vessel into which was quantitatively introduced a sample solution, i.e. 2 to 5% of test blood corpuscles suspended in saline solution, and a specified antiserum, i.e. anti-A- or anti-B-serum. Then, the mixture was held stationary for reaction between blood corpuscles and antiserum. Subsequently, it was centrifuged to sediment blood corpuscles. Then, the reaction vessel was rapidly wobbled such that the sedimented blood corpuscles were forcedly separated one from the other and then relatively slowly wobbled so as to collect the clumped compositions in the center portion of the base surface of the vessel and form settling patterns, thereby photometrically detecting these patterns.
Such conventional blood type identifying method in which sedimentation is effected and then the reaction vessel is rapidly wobbled so as to separate the sedimented blood corpuscles from the base surface of the vessel can only be applied to the analysis of regular ABO blood type, which shows strong agglutination, but could not be applied to many other immunological agglutination reactions which show weak agglutination, for example, a method of determining Rh blood subtype or detecting various kinds of incomplete antibodies. That is, if the agglutination reaction is weak, the blood corpuscles or the like which have been clumped together become separated one from other when the reaction wheel is wobbled, and as a result, the particles are not collected in the center portion of the reaction vessel.
Further, in this known method, in order to effect the accurate judgement of the blood type, it is necessary to prepare a substantial amount of the sample blood cells and thus, required amounts of standard antiserums are increased accordingly. Nowadays, a very large number of test items are to be effected for respective patients and thus, required amounts of the sample blood for respective items must be decreased as small as possible.
The applicant has proposed in a Japanese Patent Application Laid-open Publication No. 146,044/80 a blood type judging method in which not only blood types due to natural antibodies showing strong agglutination, but also blood types due to incomplete antibodies having weak agglutination can be judged very precisely, while necessary amounts of the blood samples can be minimized. In this method, use is made of reaction vessels having conical bottom surfaces and blood cells in blood samples to be analyzed are delivered into the reaction vessels together with standard antiserum reagents. After sufficiently mixing the samples and reagents, the mixtures are kept stationary for a relatively short time such as thirty minutes and then agglutination patterns formed on the bottom surfaces of reaction vessels are detected to identify the blood type. In this method, when the sample blood cells react with the antiserum, blood cells settling down on the inclined bottom surface of reaction vessel are combined with each other and are deposited uniformly on the bottom just like as snow. When the blood cells do not react with the antiserum, the settling cells are not agglutinated and roll down along the inclined bottom surface and are collected at the lowest bottom center. Therefore, by photoelectrically detecting the patterns formed by blood cells settled on the bottom surface, it is possible to identify the blood type. According to this method, since the reaction vessels are kept stationary during the reaction and detection steps, various kinds of antibodies and antigens such as HBs antigen and syphilis antibody can be effectively detected.
However, the known analyzer for effecting the above method has still several drawbacks in that the analyzer becomes large in size and that the treating ability is low, because only a small number of samples can be set in the analyzer at one time.